The honest answer is: It depends entirely on the product in question, and the gap between the best and weakest supported options on the market is much larger than the marketing from both sides would suggest. Here is what the evidence actually shows, category by category.
Melatonin: truly effective, but only for a specific problem
Melatonin has one of the larger evidence bases of any sleep supplement, but its efficacy is specific to circadian timing issues, jet lag, shift work, and a shifted sleep window, not for insomnia in general. Clinical research supports doses in the range of 0.5 to 3 milligrams, significantly less than what many commercial products now contain, and higher doses have not shown meaningfully better results. For someone whose sleep problem is truly circadian, the evidence is solid. For someone whose problem is stress-driven or airway-related, melatonin addresses a mechanism that was never the cause.
Magnesium: moderate support, often exaggerated
For magnesium, there is clinical evidence for improved sleep quality, especially in people with magnesium deficiency and in older adults. The suspected mechanism acts through its role in regulating GABA, a calming neurotransmitter. The effect sizes in the available studies are moderate overall, and much of the more dramatic marketing surrounding magnesium in the current wellness market outpaces the actual state of research.
Valerian and herbal blends: weak, inconsistent evidence
Valerian is among the most commonly used herbal sleep aids, and simultaneously among the most inconsistently supported. Systematic reviews of valerian studies find mixed results; some studies show moderate benefit, others no significant difference compared to placebo. Researchers usually attribute this pattern to inconsistent extraction methods and dosages of the various products; there is no conclusive answer as to whether the plant itself works.
CBD: promising, but still very early
Research on CBD for sleep is growing rapidly, but clinical evidence in humans remains comparatively limited. Most existing studies have small sample sizes or measure anxiety rather than sleep directly. Early research points to a potential benefit, especially for sleep disorders associated with anxiety, but sleep researchers remain cautious overall about treating CBD as an established sleep intervention because current market euphoria has significantly outpaced the size and quality of the evidence base.
Weighted blankets: moderate, real, but limited evidence
Several smaller studies show that weighted blankets can improve subjective sleep quality and shorten the time it takes to fall asleep. The suspected mechanism acts through deep pressure stimulation and its effect on the nervous system. The evidence is real, but limited in scope, and the effect appears to be clearer for anxiety-related sleep problems than for sleep disorders with other causes.
Sleep trackers: useful for patterns, not for diagnoses
Consumer sleep trackers have gotten significantly better, but validation studies compared to clinical polysomnography continue to find relevant inaccuracies, especially in the precise differentiation of sleep stages. Their true value lies in identifying patterns over time—a regular dip in sleep quality in a specific week of the cycle, a constant disturbance after alcohol—not in a clinically exact night-by-night evaluation.
Nasal strips and airway aids: real mechanism, evidence for broad application still in development
The mechanism behind nasal strips, the support of airflow through a mechanically narrowed nasal passage, is well-documented in airway physiology. Less clear is how much someone without a discernible narrowing benefits from nightly use. The honest position, also held by sleep physicians regarding this category: The tool is most clearly useful for people with an identifiable restriction of nasal airflow, not as a universal nighttime add-on with guaranteed benefits for everyone.
Where NMN stands in this assessment
NMN belongs in a different category than most of the above because its target is not sleep directly, but NAD+, the coenzyme that activates SIRT1, the protein behind the precision of the circadian clock. The clinical study situation is smaller than with melatonin, but mechanistically more specific than with most herbal options: A randomized, double-blind, placebo-controlled 2022 study in the journal Nutrients found significant improvements in sleep quality scores in adults who took NMN daily for twelve weeks. As with most of the categories above: The research base is real, but still in development compared to more established interventions, and any claim that goes beyond what the published studies themselves report deserves the same skepticism as in any other category on this list.
The honest assessment framework for all of it
The products with the strongest evidence share three characteristics: a concrete, identified mechanism, a dose that corresponds to what was actually studied, and a defined target group in which the research took place. A product that promises broad, dramatic effects for everyone, in a dose or formulation that was never directly tested, is claiming something that the evidence does not support, no matter the category. The question worth asking is never simply "does it work." It is "for which specific problem, in which target group, in which dose was this actually shown," because that is precisely the question most sleep marketing tries to avoid.